Immunoregulatory abnormalities have been shown to exist in a wide variety of "autoimmune" and chronic inflammatory diseases, including systemic lupus erythematosis, chronic rheumatoid arthritis, type I and II diabetes mellitus, inflammatory bowel disease, biliary cirrhosis, uveitis, multiple sclerosis and other disorders such as Crohn's disease, ulcerative colitis, bullous pemphigoid, sarcoidosis, psoriasis, ichthyosis, and Graves ophthalmopathy. Although the underlying pathogenesis of each of these conditions may be quite different, they have in common the appearance of a variety of autoantibodies and self-reactive lymphocytes. Such self-reactivity may be due, in part, to a loss of the homeostatic controls under which the normal immune system operates.
Similarly, following a bone-marrow or an organ transplantation, the host lymphocytes recognize the foreign tissue antigens and begin to produce antibodies which lead to graft rejection.
One end result of an autoimmune or a rejection process is tissue destruction caused by inflammatory cells and the mediators they release. Antiinflammatory agents such as NSAID's and corticosteroids act principally by blocking the effect or secretion of these mediators but do nothing to modify the immunologic basis of the disease. On the other hand, cytotoxic agents such as cyclophosphamide, act in such a nonspecific fashion that both the normal and autoimmune responses are shut off. Indeed, patients treated with such nonspecific immunosuppressive agents are as likely to succumb from infection as they are from their autoimmune disease.
Cyclosporin A which was approved by the US FDA in 1983 is currently the leading drug used to prevent rejection of transplanted organs. The drug acts by inhibiting the body's immune system from mobilizing its vast arsenal of natural protecting agents to reject the transplant's foreign protein. Though cyclosporin A is effective in fighting transplant rejection, it is nephrotoxic and is known to cause several undesirable side effects including kidney failure, abnormal liver function and gastrointestinal discomfort.
Newer, safer drugs exhibiting less side effects are constantly being searched for in the field.
The 23-membered tricyclo-macrolide immunosuppressant, tacrolimus, FR-900506, FK-506, ##STR3##
(17-allyl-1,14-dihydroxy-12-[2'-(4"-hydroxy-3"-methoxycyclohexyl)-1'-methyl vinyl]-23,25-dimethoxy-13,19,21,27-tetramethyl-11,28-dioxa-4-azatricyclo-[2 2.3.1.0.sup.4,9 ]-octacos-18-ene-2,3,10,16-tetraone) and related compounds which were isolated and characterized by Tanaka, Kuroda, and co-workers at Fujisawa Pharmaceutical Co. in Japan, see J. Am. Chem. Soc., 1987, 109, 5031, and U.S. Pat. No. 4,894,366, issued Jan. 16, 1990) have been shown to possess exceptional immunosuppressive activity. Fujisawa United States patents (U.S. Pat. No. 4,929,611, issued May 29, 1990, U.S. Pat. No. 4,956,352, issued Sep. 11, 1990 and U.S. Pat. No. 5,110,811, issued May 5, 1992) disclose the use of FK-506-type compounds in treating resistance to transplantation. In particular, the compound FR-900506 has been reported to be 100 times more effective than cyclosporin in the suppression of in vitro immune systems (J. Antibiotics 1987, 40, 1256). In addition, these compounds are reputed to possess topical activity in the treatment of inflammatory and hyperproliferative skin diseases and cutaneous manifestations of immunologically-mediated illnesses (EPO Pub. No. 0,315,978).
The compound FK-506 and related compounds further have been suggested to be useful in the treatment of obstructive airways disease, particularly asthma (PCT Publication WO 90/14826), male pattern alopecia or alopecia senilis (EPO Publication No. 0,423,714), rheumatoid arthritis (C. Arita, et al., Clincial exp. Immunol., 1990, 82, 456-461; N. Inamura, et al., Clin. Immunol. Immunopathol. 1988, 46, 82-90), recent-onset diabetes (N. Murase, et al., Diabetes, 1990, 39, 1584-86; N. Murase, et al., Lancet, 1990, 336, 373-74), posterior uveitis (H. Kawashima, Invest. Ophthalmol. Vis. Sci., 1988, 29, 1265-71), hepatic injury associated with ischemia (M. Sakr, et al., Life Sci., 1990, 47, 687-91) allergic encephalomyelitis (K, Deguchi, et al., Brain Nerve, 1990, 42, 391-97), glomerulonephritis (J. McCauley, et al., Lancet, 1990, 335, 674), systemic lupus erythematosus (K. Takabayashi, et al., Clin. Immunol. Immunopathol., 1989, 51, 110-117) multidrug resistance (M. Naito, et al., Cancer Chemother. Pharmacol., 1992, 29, 195-200), inflammation of mucosa and blood vessels (PCT Publication WO 92/17754), cytomegalovirus infection (UK Publication GB 2,247,620A), and idiopathic thrombocytophenic purpura and Basedow's disease (PCT Publication WO 91/19495).